In this paper, the authors revise the sub-family Atactorhynchinae Petrotschenko, 1956, after studying types of Floridosentis mugilis (Machado Filho, 1951) and material recovered from intestine of Mugil sp. from Cabo Frio, Estado do Rio de Janeiro, Brasil. They confirm what was suggested by Bullock, 1962, about a new combination for the type species of Floridosentis Ward, 1953. For this reason, they make F. elongatus, synonym of F. mugilis Machado Filho, 1951. Besides they also enlarge the subfamily diagnosis and add a table showing the maind differences between the two genera under Atactorhynchinae Petrotschenko, 1956.